I do a lot of dryer vent installation work, most of which is to replace venting that has either seen better days, or simply was not installed correctly to begin with. And until laundry rooms on the second floor of homes became popular, most of this venting took its journey to the outside world via the homes crawlspace. But sometimes, getting from the back of the dryer to the outside isn’t as easy as is should be.
Most home designs, at least in my neck of the woods, are built upon a raised foundation leaving the correctly named crawlspace as the place for the homes mechanical systems. This will include most plumbing, HVAC, dryer venting (of course), and in some cases electrical. And although much of these system don’t actually take up much space, they can prove to be a challenge when located in close proximity to one another.
Laundry rooms (where the dryer resides) will always have plumbing close by and in may older homes, the water and home heating systems too. When updating a dryer vent installation, finding a way to get everything to work together while providing for proper function can be a challenge, but the benefits are well worth the effort.
Take for example the dryer venting in the photos in this post. Because of the proximity of an HVAC duct as well as a floor joist, the venting was made of flexible metal. This flexible ducting (or transition hose as we call it) is used for many other home venting designs, but is far from effective when used as dryer venting. Because of the lack of a smooth interior wall and poor ability to resist the pull of gravity, most of these ducts become clogged with lint and begin to fall to the ground. Plus as the venting is bent around objects, the 4 inch interior dimension begins to close in and actually reduces the airflow. Once the airflow begins to slow, the problems begin to mount.
The key is to not only use proper code compliant materials, but to also design a system to move air in as straight a line as possible. The international mechanical code for dryer vent installation is very clear about what types of materials should be used and in same cases, how it should be run. But most work in existing crawlspaces means the beginning and ends are set points and only the middle can change. The use of smooth transitions and avoiding sharp bends is really the key to keeping the air moving properly. Properly taped joints and strapping to maintain structural integrity are also key in any design work.
Many times other mechanical systems need to be worked around for a proper dryer vent installation. There really is no other way around it, but with proper planning and using the right materials, it is possible to keep the air moving from the dryer and limit future problems.
Dryer Tech has been performing dryer vent installation work in homes and businesses in the Portland metro area for over 5 years.